Werowance attempts Upshur Vertical Single

Discussion in 'A Work In Progress' started by werowance, Oct 29, 2019.

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  1. Jan 24, 2020 #121

    Brian Rupnow

    Brian Rupnow

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    Tappets and lifters are basically the same thing. The lobe of the cam slides across the face of these tappets to lift the tappet against the pressure of the valve spring. A cam follower is round like a bearing, and the lobe of the cam makes the cam follower roll like a bearing as it is actuated. There is a bit of voodoo involved with the cam design, depending on what type of tappet or cam follower is used. The cam lobe which interacts with a flat tappet should have rounded flanks, otherwise, if there was no rounded flanks, only flat sides, then the flat side of the cam can "slap" against the flat face of the tappet. Cams which interact with a cam follower can have flat flanks, since the cam follower is round and there are not two flat faces to "slap" together. On older cars, the tappets or lifters were solid. This meant that the old engines would get noisy as surfaces wore and the valve lash became greater, requiring that every so often you had to adjust the clearances in the valve train. Then some bright spark had an idea---Lets make the tappets two piece, like a mini hydraulic cylinder. Then we can bleed some of the engines pressurized oil thru galleries to the tappets, and no matter how much slack wears into the valve train, the two piece hydraulic tappets will extend to take up the slack, thus doin g away with the necessity to manually set the valves.
     
  2. Jan 25, 2020 #122

    ALEX1952

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    We were taught how to grind a drill for flat bottom holes, as the hole acts as a drill guide no pilot is required and chatter should not be a problem, this was a perfectly acceptable method then and I see no reason why it should not be used now.
     
  3. Jan 27, 2020 #123

    werowance

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    Just a few parts this weekend. Breather tube, cap and the tappet guides
    IMG_0417.JPG IMG_0418.JPG IMG_0419.JPG
     
  4. Jan 28, 2020 #124

    werowance

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    getting close to cutting my gears for this, i have made a few gears but always had trouble calculating the depth of cut. i found this site http://computers.martinchick.com/spur_gear.html with a gear calculator on it and seems everything corelates with what pic design says (the recomended place to buy the gears in the plans) but when i do the calculator it gives me 2 depth outputs.

    1 - working depth (i assume this is the depth the mating gear tooth will go into the matching v groove ?)
    2- whole depth (i assume this is the actual depth of the "V" that i cut ?)

    if my 1 and 2 questions are correct then this calculator will be really handy for me.
     
  5. Jan 28, 2020 #125

    awake

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    You got it - the gear cutter has to cut a bit more than just the working surface of the gear teeth; it also has to cut some clearance. Thus, whole depth = working depth + clearance.

    A word of warning, however. There are formulas (for example, in Machinery's Handbook) for each of the parameters of any given spur gear. For the most part, the formulas I have seen in different sources are identical as far as math, but sometimes differ with regard to abbreviations used. However, clearance is a calculation that often involves some slight differences in the formula - differences that may depend on the module or DP of the gear, but also differences in how the clearance calculation may be simplified. I've attached one chart of formulas that I have often used, but I will warn you that this definitely does include some simplification of the clearance for smaller pitch gears.

    Fortunately, what we're fussing over is clearance - a little bit more or less clearance is not a problem, so long as it is enough. Unfortunately, it doesn't really matter which formula YOU use to calculate the clearance (and therefore the whole depth); what matters is the formula used by the manufacturer of the gear cutter. If they have a bit of extra clearance, that needs to be included in the whole depth used for that cutter. Ideally, therefore, the whole depth should be marked on the cutter itself. If it isn't ... then do your own calculation, cut some samples, and see what you get.
     

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  6. Jan 28, 2020 #126

    werowance

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    Thank you for that. i did read that depth should be marked on them on another site but mine do not. just the module number, the teeth it can cut like 31-36 (made up number just for example) and the 20deg for the PA of the gear is all that is marked on mine.
     
  7. Jan 28, 2020 #127

    awake

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    What's the module? Let's say it is module 1. My simplified chart calls for a clearance of 25% of the addendum, which for metrics gears is conveniently the module. So we are talking about a clearance of .25mm = .010". If that changes to, say, 20% clearance, .2mm = .008 - a whopping difference of .002". Probably within the fudge factor that you might use anyway ... I think you are safe to use the numbers that the calculator gave you. :)
     
  8. Jan 28, 2020 #128

    werowance

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    module 1, and thank you so much. that calculator really simplifies things for me. have 1 gear blank ready and will get the other one ready hopefully tonight so I can cut gears this weekend. only other set of gears that actually got used were in the Webster. they turned out pretty good though. I think I just got lucky though on those :)

    on the blanks, I'm making them long enough to get a few spares out of one gear cutting session.
     
  9. Jan 29, 2020 #129

    stanstocker

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    Greetings,

    The depth calculation for module based spur gears is 2.25 * module. While most US folks commonly deal with "pitch" (10,12,16,32 etc.) the ISO specifications using module based cutters can sometimes make the calculations nice and easy.

    A nice summary of ISO spec cutting of many gear forms is found at:
    https://khkgears.net/new/gear_knowledge/gear_technical_reference/calculation_gear_dimensions.html

    Fortunately the spur gear part is right at the start, some of the more complex forms require a bit more complicated math.

    You may encounter some weird numbers when looking for information on using module cutters as these are very common in clock work. Clock gears usually have cycloidal rather than involute teeth. Many antique clock gears were not cut to any standard other than the cutters made in the shop and you start getting depths, tooth thicknesses, and addendum/dedendum ratios all over the place.

    In clock work depthing tools are often used to check gear mesh. When dealing with gears mounted on shafts the tool starts to get harder to make with sufficient accuracy, when you have just the gears simpler methods work fine. As the center distance of the gears is already defined, you might take a few minutes and press two pins into a small plate with this distance drilled carefully. Add a couple bushings or make the press in pins stepped to fill the center hole of the gear and you can test the mesh of the gears as they rotate without having other parts limiting your sense of touch. A nice smooth rotation through a few complete turns is what you are after. A posh adjustable flat depthing tool is show at:
    http://www.clickspringprojects.com/pinion-head-depthing-tool.html

    It's looking like a nice project, I've enjoyed following it!
    Stan
     
  10. Jan 29, 2020 #130

    awake

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    I have gear specifications from gear manufacturers that state the clearance for this size of gear as 25% of addendum (conveniently, addendum = the module for metric gears) ... or 20% ... and in very old editions of MH, 15.7%. Which is to say, the whole depth could be anything from 2.25 * module to 2.157 * module. But again, the net effect in a module 1 gear is a maximum of .004". So if you cut them at a whole depth of .085" (=15.7% clearance), you might find that the gears bind a bit ... and if you cut them at a whole depth of .089" (=25% clearance), you might get a bit more backlash than you wanted ... but in either case, the actual result will also depend on how precisely you locate the gear axes.
     
    Last edited: Jan 30, 2020
  11. Feb 3, 2020 #131

    werowance

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    Gears turned out good this weekend. But I did mess up the first 30 tooth. Math was all correct but I must have hit my indicator or something before I locked everything down to cut it. First cut was way to deep. I made a couple extra passes just so I could see how bad it was then reset everything back up this time double checking everything and finished cutting the gear just so I could test the fit before making a new one. It fit great. The 60 tooth came out just fine. I cut a few extras of each while I was at it

    IMG_0423.JPG IMG_0424.JPG
     
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  12. Feb 3, 2020 #132

    awake

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    I've made a few gears that look like that first picture. :)

    Good work on the rest!
     
  13. Feb 3, 2020 #133

    Brian Rupnow

    Brian Rupnow

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    Nice work on the gears. As you found out, you have to really pay attention to the math and set-up, and you really don't want distractions. Gears are a milestone for model engine builders, and you've done good.---Brian
     
  14. Feb 3, 2020 #134

    CFLBob

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    Add me to the impressed - nice looking. What did you cut those in? I think it looks like steel but that's not saying much.
     
  15. Feb 3, 2020 #135

    werowance

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    I cut them in 12L14 steel
     
  16. Feb 4, 2020 #136

    bobden72

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    Nice job on the gears.
     
  17. Feb 5, 2020 #137

    werowance

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    well all I can say is CRAP! day before yesterday I went home and was planning on marking the side plate to cutout a slot for the gear to clear and low and behold I had made a mistake. I reamed the holes in the gears for the opposite shafts they were to ride on. in other words the cam gear was reamed for the crankshaft and the crank gear was reamed for the camshaft. I tried to enlarge the one gear to fit the crank but it turned out off center. oh well both gears are junk for this project.

    so with that I am taking a few days off from machining so I can as my wife calls it pout about it.
    maybe Ill have my head out of my rear end after a few days off and can cut them correctly.
     
  18. Feb 5, 2020 #138

    awake

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    Oh, I feel your pain. This is when I pull out the old proverb ...

    I've cut it three times, and it's still too short!

    :)
     
  19. Feb 7, 2020 #139

    John Antliff

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    What a shame - I'm glad I'm not the only one. I offered to shave off an 1/8th from the bottom off my friends door only to find out when re-hanging it that I had actually taken an 1/8th of the TOP. How could I do that?
     
  20. Feb 19, 2020 #140

    werowance

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    I haven't gone away or anything. just took a week off then had multiple failures when I started back, then a round of the stomache virus for about 4 or 5 days....

    I over shot the mark when turning down the gear blanks at least twice, then when cutting the 30 tooth gear my draw bar came loose and my chuck dropped. some how that ruined the teeth on the 30 tooth gear cutter (fortunately the machine was not damaged). that cutter was an oddball brand that did not match the rest of my mod 1 set anyway. I have ordered another one of a matching brand from Australia and in the mean time the 60 tooth came out just fine and meshes with the original 60 tooth really nice as a test. I have not parted it off yet though. hopefully Ill have the new 30 tooth cutter any day now and when I get it cut ill part both gears off. my lathe is a combo lathe mill so I don't want to switch back and fourth until I have to. in the mean time I have started thinning down some bronze I had for the rocker arms that was close to the right thickness to begin with.

    upload_2020-2-19_10-2-40.png

    upload_2020-2-19_10-3-43.png
     

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